In the current art, liquid alkaline, hypochlorite compositions are commonly employed in such applications. Such compositions generally contain strong alkali, suitably, potassium or sodium hydroxide, in the range of 5 to 15% to saponify fats; sodium or potassium hypochlorite at levels providing 1.5 to 4% available chlorine to break down protein; and suitable levels of various hypochlorite stable chelating and/or sequestering agents to tie up the water hardness minerals at the desired product usage level.
In usage, the concentration of the products of this type is diluted with water at ratios of between about 1:320 (1 oz. cleaner to 5 gallons of water) to about 1:40 (1.5 oz. cleaner per gallon water). Most of these compositions result in satisfactory cleaning results provided the mechanical effect, temperature, and time of the wash cycle is sufficient. However, in the case of difficult cleaning conditions due to the design or nature of the equipment or other conditions, such as high soil loads, too low cleaning temperature or lack of time of cleaning, the current art of alkaline hypochlorite cleaners do not provide satisfactory results.
One way to overcome these cleaning difficulties would be to improve the performance of the cleaner composition. This could be accomplished by the lowering of surface tension and interfacial tension by introducing a surface-active agent into the composition. It has long been established that lowering surface tension of the cleaning solution increases its cleaning properties. More recently, studies made by scanning electron microscope of stainless steel surfaces demonstrate that microscopic ridges and grooves are present which allow the enhanced attachment and growth of bacteria which then contaminates food or milk that comes into contact with it. The improved surface cleaning properties of alkaline, hypochlorite compositions containing surface active agents may reduce entrapped food particles and microorganisms harbored in these surface irregularities, in addition to the general enhancement of emulsification of fats and removal of proteinaceous soil loads.
The current art does not allow for the incorporation of satisfactory surfactants into such cleaning compositions. Some surfactants which are relatively stable to hypochlorites are not soluble in such systems containing high concentrations of electrolyte salts. Various surfactants which show stability to hypochlorites and are electrolyte tolerant to high levels of neutral salts show poor hypochlorite stability in more strongly oxidative, highly alkaline hypochlorite solutions typical of the food industry and dairy equipment cleaners. Furthermore, the few surfactants which overcome the aforementioned stability problems foam to such a high degree as to preclude their use in mechanical cleaning systems.
Typical mechanical cleaning in the food industries and dairy farm are performed by circulation and/or spraying and are termed C.I.P. (clean-in-place) or C.O.P. (clean-out-of-place). C.I.P. systems operate under especially demanding conditions using high-fluid velocities, high pressure and/or vacuum, spray, etc. such that even low to moderate foaming surfactants generate extremely high foam. This in turn leads to a decrease in cleaning performance by inhibiting the proper functioning of the C.I.P. system, and in extreme cases may even lead to the shutdown of the system. Milking equipment C.I.P. systems are certainly the most challenging equipment to clean. The relative vacuum existing in such systems during cleaning, combined with relatively low operating temperatures, air intake, and saponifications of milk soil tend to make cleaning solutions high foaming.